冰山模型。文档是采用思维导图的形式记录的，需要用mindmaster打开。
参考资料：https://blog.csdn.net/weixin_38004638/article/details/103171410?ops_request_misc=%257B%2522request%255Fid%2522%253A%2522158598995019726869026419%2522%252C%2522scm%2522%253A%252220140713.130056874..%2522%257D&request_id=158598995019726869026419&biz_id=0&utm_source=distribute.pc_search_result.none-task-blog-all_SOOPENSEARCH-3
